1. Field of the Invention
Apparatuses consistent with the present invention relate to an inverter power module in the form of one board forming a power supply, which is used in driving a backlight of a liquid crystal display (LCD) device, such as an LCD monitor, an LCD television (TV), etc.
2. Description of the Related Art
The latest power supply for use in an electric/electronic device is tending toward using an inverter and a power transformer that are integrally formed on a single driving circuit board. A typical example of such an inverter power module for use in the electric/electronic device is illustrated in FIGS. 1 and 2, and a construction thereof is briefly explained as follows.
As illustrated in FIGS. 1 and 2, a general inverter power module 1 is configured, so that a power transformer 20, an inverter transformer 30 and a plurality of elements (not illustrated) are mounted on a driving circuit board 10. The inverter transformer 30 is provided with a bobbin 31 having a plurality of lead pins 31a connected to the driving circuit board 10, a first core 32 disposed in the bobbin 31, a coil 33 wound on the bobbin 31 and connected to the lead pins, and a cover 34 to accommodate the bobbin 31, the first core 32 and the coil 33.
In the general inverter power module 1 constructed as described above, a magnetic flux is generated from the inverter transformer 30 as a single inverter transformer 30 drives a plurality of LCD lamps (not illustrated) in parallel. Such a magnetic flux is emitted to heat sinks (not illustrated) or shields (not illustrated) around the inverter power module 1.
However, since the general inverter power module 1 does not block the magnetic flux generated from the inverter transformer 30 from being emitted to the outside, a problem occurs, in that an electromagnetic interference (EMI) noise is greatly generated due to the emission of the magnetic flux to the outside. For instance, as illustrated in FIG. 3, an EMI noise exceeds a generally acceptable threshold (see one-dotted line in FIG. 3) by approximately 10 dB (see dotted line in FIG. 3) in an area A due to the magnetic flux.
In addition, since the magnetic flux is transmitted to the heat sinks or shields around the inverter power module 1, a problem occurs, in that heat is generated and thus a lifespan of product is reduced.
Also, due to the emission of the magnetic flux to the outside, a problem occurs, in that a noise is generated in surrounding circuits, thereby causing the system circuit to malfunction.